(1) Drilling Rig Automatic Control Test Technology and Platform

The automatic and intelligent drilling rig is one of the most important development directions of drilling rig technologies in the future, and its core technology lies in the control system hardware and the control software. The reliability and stability of the control system directly affect the efficiency, safety and applicability of other unit equipment and are also the core bottleneck that restricts the development of drilling rig technologies in China for a long time.

In order to completely reverse the unfavorable situation of low automation of drilling rigs in China and realize the leapfrog upgrade of drilling rig technologies, the Drilling Equipment Engineering Center has integrated the disciplines of power electronics, electronic information, process control, electromechanical control, programmable control, detection sensing, instrumentation and so on into the drillingrig control system experiment, designed and developed the domestic leading-level rig automatic control experimental platform. The platform is composed of the drilling rig automatic control laboratory and the drilling rig equipment comprehensive test bench, and has the functions of hardware and software development and testing of the control system, and system and unit testing of the automatic drilling equipment and the like. So far, the established automatic control test platform has played a key role in the research and development of "Oil Rig Automatic and Intelligent Technologies" and "Automatic Pipe Handling System" in the Planning Assignment.

a. Drilling Rig Automatic Control Experiment

Aiming at the situation that the domestic automatic drilling rig technology is still in its initial stage and is not verified by the relevant professional laboratory, the National Engineering Research Center for Oil & Gas Drilling Equipment has developed the control program test platform based on digital prototype for the first time in China in order to meet the needs of comprehensive testing of the control system of newly-developed equipment.

The test platform uses the virtual reality simulation technology, communicates and docks with the newly-developed control program through establishing the digital prototype of the controlled equipment and the motion driver, and the R&D personnel can use the physical console to issue control instructions and drive the digital prototype to act, and then verify the rationality of the control program.

The test platform can realize the pre-test and evaluation of the hardware equipment, software program, man-machine operation interface, etc. of the product control system before the physical prototype is trial-produced, which can greatly shorten the research and development cycle and reduce the safety risk in the field debugging. The technical level of this experimental system is leading in China.

b. Drilling Rig Equipment Comprehensive Test

With the continuous improvement of the efficiency, safety and cost control requirements for land and offshore oil and gas drilling, the new drilling equipment represented by the automatic pipe handling system will become a very important configuration of drilling equipment, and has great development potential. In view of the current situation that there is no comprehensive test device of the professional pipe automatic handling system and other equipment in China, the first comprehensive test bench of drilling rig equipment in China is designed independently in combination with the needs of new product development of the National Engineering Research Center for Oil & Gas Drilling Equipment.

The test bench can simultaneously meet the debugging needs of two types of automatic pipe handling systems of land and offshore drilling rigs, the unit debugging or system joint debugging of multiple devices such as the grabbing crane, iron roughneck, power rat hole, automatic derrickman, racking platform manipulator and so on can be carried out, which effectively reduces the risk of new product development. At the same time, the Center uses this device to innovatively realize the test and verification of the offshore drill string heave compensation equipment, the marine riser tensioner and other new marine products. Therefore, the device has played and will continue to play an important role in breaking the foreign technology monopoly of pipe automatic handling.

(2) Marine Riser Fatigue Test Technology and Platform

Marine risers, including the deep-water drilling riser and the oil production riser, are the key equipment for offshore deep-water oil and gas exploration and development. During the drilling operation, the service environment of the deep-water drilling riser is harsh and the stress state is complex, including the tension force from the top tensioner and the buoyancy material, the bending load from the drift of waves, tidal currents and floating platforms, the dynamic load caused by the acceleration of ocean currents, and the pressure inside and outside the string. In order to ensure the safety of marine risers in complex environments such as waves and currents, and to avoid drilling accidents and disastrous consequences, it is of great importance to test the fatigue life of marine risers.

In order to break the long-term blockade of the full-size fatigue test technology of foreign marine risers and improve the level of the riser design and manufacturing technology in China, the Center has deeply studied the marine riser test and evaluation technologies, and designed the domestic first marine riser resonance bending fatigue test device and the marine riser welding test device, which are used for the marine riser fatigue life test and the marineriser full-size welding process technology research and pilot production. The test platform has played an important role in the research and development of "Marine-Riser Design and Manufacturing Technologies" and "Class-E Marine Drilling Risers" in the Planning Assignment.

a. Marine Riser Resonance Bending Fatigue Test

The marine riser resonance bending fatigue test device adopts the resonance bending principle, and is applicable for the pipe fatigue specimens with the diameter of φ203mm-φ560mm and the length of less than 12m, the load varies periodically in the sine-cosine form, the maximum loading speed is about 100,000 times / hour, and the internal loading pressure of the pipe can reach 105MPa. The device can be used for full-size bending fatigue tests of large-diameter pipes such as the marine drilling risers, oil recovery risers, oil casing and its connecting joints. The test device is the first in China, breaks the long-term technical monopoly of full-size fatigue tests of foreign offshore deep-water risers, and has obtained 1 technical patent. After completion, the device was used to conduct the full-size fatigue test for the independently-developed 2 class-E deep-water drilling risers and the loading speed was about 86,000 times/hour. The test results showed that the fatigue life of both samples exceeded the F2 target curve stipulated in the BS7608 standard and met the design indicators.

b. Marine Riser Welding Test

The marine riser welding technology is one of the key technologies in the marine riser manufacturing process, and has been monopolized by European and American countries for a long time. Its difficulties lie in the various varieties and specifications of materials involved, large difference, extremely-high requirements for welding quality and performance, and numerous test items for process evaluation. Therefore, the Center has jointly designed the marine-riser welding device, which is used to carry out the research on the welding process and welding materials of various specifications of marine risers and the pilot production of products.

The device is the highly-integrated automatic welding test equipment which integrates the marine riser assembly welding machine, submerged-arc welding, gas-shielded welding, argon-arc welding and various combined welding methods, has the functions of welding in circular welds, which is the first in China. This device has been used to produce 4 class-C marine drilling risers and complete the fatigue test.

(3) Test Technology and Platform of Subsea Wellhead Equipment

The subsea wellhead equipment includes the subsea wellhead device, the subsea connector, the subsea oil Christmas tree and other equipment, and is the indispensable key equipment in offshore oil drilling and production. The equipment stress state under submarine conditions is very complicated; it not only suffers the environmental loads such as waves and currents, as well as the tensile (compression) and bending loads of the marine riser, and also bears the large dead weight, internal pressure and external pressures and other loads.

The design and manufacturing technology of subsea wellhead equipment has been monopolized by developed countries in Europe and the United States. In order to accelerate the development of subsea wellhead equipment in China, ensure the offshore oil strategic safety in China, and build the corresponding subsea simulation test platform, it is urgent to test the working performance and reliability of the subsea wellhead equipment in extreme environments. Therefore, the Drilling Equipment Engineering Center has developed the subsea wellhead equipment test platform, which is used to carry out relevant experimental researches and tests to all kinds of subsea wellhead devices, subsea connectors, and subsea oil Christmas trees and so on. The main test unit devices fill the relevant gaps in China and reach the international leading level. This test platform has played an important role in the research and development of "Offshore Deep-water Wellhead Equipment and Control Technologies" and "18 3/4-10000psi Subsea Wellhead Devices" in the Planning Assignment.

a. Bending Load Test

Under the joint action of various loads, the subsea wellhead equipment may lead to the collapse of the whole wellhead and even lead to serious accidents such as offshore crude oil leakage when the borne bending moment value exceeds the design limit.

In order to improve the technical level of the bending load test for the subsea wellhead equipment and provide a means to verify the bending performance for the development of new products, the Center has independently developed the first bending load test device of subsea wellhead equipment in China, and has successively conquered the bending load control technology, the loading liquidcylinder synchronous control technology and the large-diameter thread fastening and anti-bonding technology.

The test device is a comprehensive test bench integrating the electricity, air and hydraulic system and used for the bending load test of the subsea wellhead devices, subsea connectors, subsea oil Christmas trees and other key devices. The maximum bending moment of the device reaches 13,500kN.m, and the device can inject the clear water with the maximum pressure of 140MPa into the tested piece when the bending load test is conducted, simulate the fluid pressure in the subsea wellhead, and realize the evaluation of the reliability of the equipment sealing surface under the bending load, and provide experimental support for the design and development of new products. The test device is used to successively conduct the bending load tests of THC18 3/4-70Z hydraulic connector and SW 18/3/4-10000psi subsea wellhead device, and all test parameters meet the design requirements.

b. Deep-water High Pressure Simulation Test

With the rapid development of offshore oil and gas exploitation to the deep sea in China, it is urgent to simulate and verify the critical equipment in the deep-water high pressure environment. The Center has developed the deep-water high pressure simulation test chamber in conjunction with relevant institutions in order to fully understand and master the technical performance of subsea equipment and ensure the safety and reliability of subsea equipment.

The test chamber is not only can be used to carry out special tests such as the external pressure test, internal pressure test, function test, power supply, signal transmission, etc. of the subsea equipment, but also can be used to test and monitor the action logic of subsea equipment in the whole process, and is the offshore oil equipment test device with the highest pressure, largest volume and most functions in the domestic petroleum industry at present. This device has been used to conduct the internal and external pressure tests for the key components of independently-developed subsea oil Christmas trees.